The present invention relates to a hard endoscope of which the hard insertion tube provided at the end of its controller is inserted into the body cavity of a patient through a trocar for viewing the cavity inside and for other purposes such as removal of tissues or secretions for biopsy, photography, air or water filling and the like, and to a sheath destined for use as attached on the hard endoscope.
Heretofore, various types of hard endoscopes have been proposed. A typical hard endoscope is known which comprises, as shown in FIG. 1, a controller 100, having control buttons and which is operated as held in hand by the operator, a hard insertion tube 101 provided at the end of the controller 100 as connected to the latter and which is to be inserted into a patient's body cavity through a trocar (not shown), and a coupling tube 103 which is to be connected to a necessary light source by means of a connector 102 and to which an external apparatus (not shown) such image signal processing unit or the 1 ire is to be connected where the endoscope is an electrical one having a charge coupled device (CCD) disposed at the front end of the hard insertion tube 101 or an external apparatus (not shown) such as a camera or video tape recorder (VTR) is to be connected.
Generally in such an endoscope, the coupling tube 103 is fixed to the endoscope body and extended laterally from the controller 100 and almost perpendicularly thereto.
When handling such hard endoscope, the operator has to turn the endoscope body about the axis of the controller 100 for the convenience of operation, for example, because of his position in relation to the patient. In this case, the coupling tube 103 will be turned along with the controller 100. An external apparatus connected to the coupling tube 103 will be displaced or the coupling tube 103 will hit the patient or operator. Also an excessive force will be applied to between the coupling tube 103 and controller 100, possibly causing failure of the endoscope.
Further, the hard endoscope is contaminated with blood or other because it is inserted into the patient's body, and so it must be subjected to sterilization or disinfection before a next endoscopy. It is sterilized in a gas, for example, EOG (ethylene oxide gas).
However, since the insertion tube of the hard endoscope is thin and long and has small-diameter passages formed longitudinally therein, that is, it has a complicated internal structure, the sterilization or disinfection requires extensive labor and time.
To save such labor and time for sterilization or disinfection, an endoscope sheath was proposed as disclosed in, for example, the Japanese Examined Patent Publication No. 2-54734. This endoscope sheath consists of a hard support having the form of a cylindrical cap, and a soft cylinder made of an elastomer or the like and wound like a roll on the hard support. This sheath is to be used as fitted on the portion of the insertion tube of the endoscope.
However, the sheath of such a structure is fitted on a short end portion of the insertion tube of the endoscope. In other words, the sheath covers only a limited length of the insertion tube portion that is inserted into the patient's body, and so the insertion tube portion left not covered by the sheath still has to be sterilized or disinfected.
For simplifying such troublesome and labor intensive sterilization or disinfection, it has been proposed to entirely cover, with a sheath, a portion of such an endoscope, which is likely to transfer its contamination to a next patient subject to an endoscopy, including the controller which the operator touches with his fingers. However, because the buttons that project at the controller, the and coupling tube extending laterally and nearly perpendicularly, etc. interfere with such full covering and for the following reasons, this sheath could not have been put into pratical utilization.
Namely, if made of a material having a large coefficient of friction such as elastomer, the soft portion of the sheath, that is to be inserted into the abdominal cavity or the like through a trocar, cannot smoothly be passed through the trocar because of its great coefficient of friction.
To avoid this, a space may be provided between the soft portion and trocar. However, as the soft portion has to keep an airtightness with respect to the trocar, the dimension of the space between the outer surface of the soft portion and the inner wall of the trocar is strictly limited. Thus, such spacing is impossible in practice. Furthermore, even if the soft portion can be passed through the trocar, a blade, if any, provided at the end of the trocar would cut and break the soft portion.